Conventional communication set-ups typically include an electronic circuit, which has a communication unit for wireless communication. For this, an antenna network connected to an antenna is provided in the communication unit. Near field communication (NFC) is a possible technology for this.
Such communication set-ups are used in various fields of application. For example, communication set-ups for wireless communication are applied to cards usable as a means of payment, such as credit cards or bank cards, in order to initiate a payment event with the aid of wireless communication. To this end, the card wirelessly transmits necessary information, such as the card number, to the receiver unit, in this case, the payment terminal, via its communication unit, using, typically, NFC technology. The use of such a card with a contactless payment transaction is technologically simple and does not require any special technical knowledge, which means that its broad use in society is enabled.
However, in the case of contactless data and information transmission, there is always the risk of unauthorized persons' attaining access to the data. Thus, unauthorized persons may elicit the sensitive data unnoticed from the credit cards by imitating a payment terminal, using a receiver unit. The receiver unit may be, for instance, a smartphone having a corresponding app (application software), which brings the unauthorized person in the vicinity of someone else's credit card and keeps him/her there. If the card has transmitted its data to the smartphone one time, the unauthorized person may execute payments himself/herself or cause other harm to the credit card owner.
Different measures for increasing security in a contactless payment event have already been put forward. Thus, for example, a wireless communication device, which includes a transceiver circuit that is configured to communicate wirelessly with another device, is described in German Patent Application No. DE 10 2014 104 303 A1. In addition, the transceiver circuit is connected to a manipulation-proof circuit. The manipulation-proof circuit itself is also connected to a processor, which is configured to exchange data with the transceiver circuit via the manipulation-proof circuit. The manipulation-proof circuit may take the form of a subscriber identity module (SIM) or also a universal integrated circuit card. Any communication between the transceiver circuit and the processor is conducted via this manipulation-proof circuit, in order to prevent unauthorized use of the data.
In addition, a communication device, which includes a wireless communication interface for wireless communication, is described in German Patent Application No. DE 10 2010 043 899 A1; the wireless communication interface including an antenna network having a resonant antenna circuit. According to German Patent Application No. DE 10 2010 043 899 A1, a deactivation device is additionally provided, which is configured to change an electrical characteristic of the antenna network, in order to deactivate the wireless communication point. In this context, the electrical characteristic of the antenna network to be changed may be an inductance, a capacitance, a resistance, an impedance or a reactance. Thus, as a result, the resonant antenna circuit is detuned by operating the deactivation device, in order, therefore, to interfere with reception or emission of electromagnetic waves via the antenna, through which communication with the communication device may ultimately be prevented.
So, in German Patent Application No. DE 10 2010 043 899 A1, one of the electrical characteristics of the resonant antenna circuit itself is forcibly changed by use of the deactivation device. Since, by nature, the electronic detuning does not take place digitally, then, accordingly, the states “communication prevented” and “communication not prevented” are also not defined clearly.
Therefore, there is a need for a communication set-up, which may be converted reliably and securely from a clearly defined, blocked state to a likewise clearly defined, enabled state, and vice versa.